Generally, subway or railway platforms are open towards train tracks to allow passengers to board trains. Therefore, accidents of passengers falling onto train tracks or colliding with trains that are entering the platforms frequently occur. In an effort to overcome the above problems, a yellow safety line is marked on a platform to recommend passengers to stand behind while waiting for a train.
However, the yellow safety line merely functions to attract attention for safety such that passengers stand back behind the safety line, but the line itself cannot actually function to block a passenger from falling onto the train track or colliding with a train.
Therefore, recently, screen doors are installed between platforms and train tracks to prevent passengers from falling or collision accidents. In such a screen door, a stationary wall and a movable door are installed between a platform and a train track, and the movable door is opened in conjunction with a door of a train only when the train stops in the platform.
However, the conventional screen door is disadvantageous in that several tens of movable doors corresponding to doors of a train are required, thus increasing the production cost and initial installation cost. Furthermore, the screen door is operated depending on a position at which the train stops. If the position at which the train stops does not correspond to that of the screen door, the screen door is not operated. As a result, the time it takes for passengers to exit and enter a train is increased, thus inconveniencing the passengers.
Particularly, in emergency situations, for example, when fire accidents occur in subways, if power is interrupted, the screen door cannot be operated. In this case, the exits through which passengers can escape from the train are blocked, thus resulting in a tragic disaster.
Furthermore, the screen door is controlled by a train and an ATO (automatic train operating) system. Only some subway stations are equipped with such ATO systems. Therefore, the screen door cannot be used in an existing subway system which has no ATO system. Eventually, there are problems in that usage efficiency and utilization range of the screen door are very limited.
To solve the problems of the conventional technique, a train platform safety device was proposed in Korean Patent Registration No. 0601112 (Jul. 19, 2006) which was filed by the inventor of the present invention.
However, in this conventional technique, the number of drive units that corresponds to the number of blocks on which wire ropes are arranged is required. As a result, excessive large volume and space are required, so that usage efficiency is limited.
Furthermore, because the wire ropes must be moved upwards or downwards at the same time depending on a position at which a train stops, it is very difficult to precisely control the safety device in consideration of the lengths of the wire ropes and stroke distances of cylinders, thus making passengers uneasy.
Particularly, a large number of drive units and related elements are required in response to the number of blocks on which the wire ropes are arranged, thus increasing the production and installation costs.
Moreover, given the height to which the wire ropes for blocking access of passengers move upwards or downwards, the height of the train platform safety device is largely increased, thus also increasing the entire size of the train platform safety device.
In addition, because the structure of the conventional train platform safety device is complex, it frequently malfunctions, thus making maintenance difficult.